A donor in general is a person, organization or government which donates something voluntarily. The term is usually used to represent a form of pure altruism, but is sometimes used when the payment for a service is recognized by all parties as representing less than the value of the donation and that the motivation is altruistic. In business law a donor is someone who is giving the gift (law), and a donee the person receiving the gift.
More broadly, the term is used to refer to any entity that serves as the source of something transferred to a different entity, including - in scientific fields - the source of matter or energy passed from one object to another.
The Online Etymology Dictionary traces the English-language word "donor" back to the mid-15th century, with origins in Anglo-French, Old French, Latin and Proto-Indo-European.[1]